scholarly journals Activation of the central melanocortin system in rats persistently reduces body and fat mass independently of caloric reduction

2018 ◽  
Vol 96 (3) ◽  
pp. 308-312 ◽  
Author(s):  
Isabelle Côté ◽  
Sara M. Green ◽  
Drake Morgan ◽  
Christy S. Carter ◽  
Nihal Tümer ◽  
...  

Recent evidence indicate that melanotan II (MTII) reduces body mass independently of caloric reduction. Because MTII induces a transient hypophagia, caloric reduction is still considered a primary mechanism for MTII-mediated body mass loss. To examine the contribution of caloric reduction to long-term body mass loss in response to MTII, we centrally infused MTII or vehicle in ad libitum fed (MTII and Control) animals in comparison with a group of animals that were pair-fed (PF) to the MTII group. Food intake and body mass were recorded daily, and body composition was assessed biweekly. The present study demonstrates that central MTII-mediated body mass loss is only partially mediated by caloric restriction, and the long-term body mass loss is independent of the initial hypophagia. More importantly, central MTII administration induced a rapid but sustained fat mass loss, independently of caloric reduction. MTII-treated animals preserved their lean/fat mass ratio throughout the study, whereas PF animals underwent a transient reduction of lean/fat mass ratio that was only normalized when food intake returned to Control level. In summary, it can be concluded that activation of the central melanocortin system in rats persistently reduces body and fat mass independently of caloric reduction.

2018 ◽  
Vol 104 (3) ◽  
pp. 900-905 ◽  
Author(s):  
Juan Tiraboschi ◽  
Antonio Navarro-Alcaraz ◽  
Dolors Giralt ◽  
Carmen Gomez-Vaquero ◽  
Maria Saumoy ◽  
...  

Abstract Objectives To describe the changes in body fat distribution (BFD) occurring over 60 months in a group of antiretroviral therapy (ART)-naive individuals starting different antiretroviral regimens. Methods A prospective ongoing fat change assessment including clinical evaluation and dual X-ray absorptiometry scan is being conducted in all consecutive patients initiating ART from January 2008. Arm, leg, trunk, and total fat as well as fat mass ratio were determined. Results A total of 146 patients were included (80% male, 40% MSM). Mean age was 44 years, HIV-1 RNA was 4.98 log10 copies/mL, and CD4 count was 254 cells/μL. The most common initial antiretroviral combination included non-nucleoside reverse transcription inhibitor (NNRTI) drugs followed by protease inhibitor (PI) and integrase strand transfer inhibitor (INSTI)-based regimens. At month 36, an increase was seen in the body mass index (BMI), total fat, trunk fat, and limb fat. The fat mass ratio (FMR) also showed a significant increase in both men and women (P = 0.001). In patients receiving NNRTI- or INSTI-based regimens (but not PIs), there was a marginal but statistically significant increase in the FMR (0.10 and 0.07, respectively; P = 0.01). Sixty-two subjects completed 60 months of follow-up. FMR showed a significant increase even in the PI group at this time point (P < 0.03). Conclusions We observed a significant increase in the fat and lean body mass in all compartments and treatment groups over 36 and 60 months. Clinically irrelevant differences were found in fat distribution regardless of the treatment group and baseline characteristics. The data suggest that current antiretroviral regimens have little impact on BFD during the first years of treatment.


2017 ◽  
Vol 95 (2) ◽  
pp. 206-214 ◽  
Author(s):  
I. Côté ◽  
Y. Sakarya ◽  
N. Kirichenko ◽  
D. Morgan ◽  
C.S. Carter ◽  
...  

Melanotan II (MTII) is a potent appetite suppressor that rapidly reduces body mass. Given the rapid loss of anorexic response upon chronic MTII treatment, most investigations have focused on the initial physiological adaptations. However, other evidence supports MTII as a long-term modulator of energy balance that remains to be established. Therefore, we examined the chronic effects of MTII on energy homeostasis. MTII (high or low dose) or artificial cerebrospinal fluid (aCSF) was infused into the lateral ventricle of the brain of 6-month-old F344BN rats (6–7/group) over 40 days. MTII suppressed appetite in a dose-dependent manner (P < 0.05). Although food intake promptly rose back to control level, body mass was persistently reduced in both MTII groups (P < 0.01). At day 40, both MTII groups displayed lower adiposity than the aCSF animals (P < 0.01). These results show that MTII chronically reduces body mass without the requirement of long-term caloric restriction. Our study proposes that food restriction helps initiate mass loss; however, combined with a secondary pharmacological approach preserving a negative energy balance state over time may help combat obesity.


2014 ◽  
Vol 64 (1) ◽  
pp. 31-47 ◽  
Author(s):  
Wen-rong Gao ◽  
Wan-long Zhu ◽  
Di Zhang ◽  
Shu-ran Sun ◽  
Zheng-kun Wang

To investigate the effect of fasting and re-feeding on energy metabolism and thermogenesis in the tree shrew (Tupaia belangeri), the changes in body mass and body fat mass, resting metabolic rate (RMR), non-shivering thermogenesis (NST), body composition, mitochondrial cytochrome c oxidase (COX) activity in liver and brown adipose tissue (BAT), uncoupling protein-1 (UCP1) content of BAT, serum leptin level and post-fasting food intake were monitored and measured. The results showed that fasting induced a significant reduction in body mass and body fat mass. Body mass was restored to the control level in re-feeding tree shrew except for the body fat. RMR and NST decreased significantly in response to fasting, and returned to the control level after re-feeding. Fasting induced significant reduction in total, but not specific, COX activity (nmol O2/min/total tissue) in liver and BAT, and UCP1 content in BAT, which was reversed after re-feeding 48 h. Fasting of 12 h induced a rapid reduction in serum leptin content. There were no post-fasting compensatory increases in food intake. Interestingly, the tree shrew did not recover adipose tissue mass, nor serum leptin levels, upon re-feeding. These results suggest that T. belangeri can adjust the status of its physiology integratively to cope with the lack of food by means of decreasing body mass, adaptive thermogenesis and serum leptin levels, and serum leptin level acted as a starvation signal to mediate predominantly the reduction in body mass and energy expenditure.


2016 ◽  
Vol 3 (12) ◽  
pp. 160840 ◽  
Author(s):  
Frédéric Angelier ◽  
Charline Parenteau ◽  
Colette Trouvé ◽  
Nicole Angelier

Although the transfer of wild animals to captivity is crucial for conservation purposes, this process is often challenging because some species or individuals do not adjust well to captive conditions. Chronic stress has been identified as a major concern for animals held on long-term captivity. Surprisingly, the first hours or days of captivity have been relatively overlooked. However, they are certainly very stressful, because individuals are being transferred to a totally novel and confined environment. To ensure the success of conservation programmes, it appears crucial to better understand the proximate causes of interspecific and interindividual variability in the sensitivity to these first hours of captivity. In that respect, the study of stress hormones is relevant, because the hormonal stress response may help to assess whether specific individuals or species adjust, or not, to such captive conditions (‘the stress response-adjustment to captivity hypothesis’). We tested this hypothesis in rock pigeons by measuring their corticosterone stress response and their ability to adjust to short-term captivity (body mass loss and circulating corticosterone levels after a day of captivity). We showed that an increased corticosterone stress response is associated with a lower ability to adjust to short-term captivity (i.e. higher body mass loss and circulating corticosterone levels). Our study suggests, therefore, that a low physiological sensitivity to stress may be beneficial for adjusting to captivity. Future studies should now explore whether the stress response can be useful to predict the ability of individuals from different populations or species to not only adjust to short-term but also long-term captivity.


1988 ◽  
Vol 254 (1) ◽  
pp. R61-R68 ◽  
Author(s):  
J. P. Robin ◽  
M. Frain ◽  
C. Sardet ◽  
R. Groscolas ◽  
Y. Le Maho

The body mass of male emperor penguins is approximately 38 kg at the beginning of the 4-mo winter fast connected with breeding, and it is an estimated approximately 18 kg in leanest birds at time of spontaneous refeeding. For a 38- to 18-kg range, we investigated the changes in the rate of body mass loss, body composition, and plasma concentrations of uric acid and urea. After the first few days (phase I) a steady state (phase II) was reached in the proportions of the energy derived from proteins and lipids with proteins accounting for a constant 4%, and the remaining 96% being from lipids. The same proportions were maintained until body mass had decreased to 24 kg. Below this value the proportion of energy derived from proteins increased progressively (phase III), being 14 times higher at 18 kg than during phase II. Rate of body mass loss and plasma uric acid and urea concentrations closely reflected the changes in protein utilization: being at a low and steady value throughout phase II and increasing during phase III. Emperor penguins also fast during the spring, but for periods of only 2-3 wk. We found a 2.5 times higher value for rate of body mass loss, uric acid, and urea during spring phase II, suggesting lower effectiveness in protein sparing at that time. It may be attributed to the lower initial lipid reserves of spring birds. Would these findings be generalized to the wide variety of birds and mammals that spontaneously fast under natural conditions?(ABSTRACT TRUNCATED AT 250 WORDS)


2021 ◽  
Vol 42 (Supplement_1) ◽  
pp. S20-S21
Author(s):  
Sandrine O Fossati ◽  
Beth A Shields ◽  
Renee E Cole ◽  
Adam J Kieffer ◽  
Saul J Vega ◽  
...  

Abstract Introduction Nutrition is crucial for recovery from burn injuries, as severe weight (wt.) loss can lead to impaired immunity and wound healing, infections, skin graft failure, and mortality. Previous studies recommended avoiding more than 10% wt. loss, as this level resulted in increased infection rates. However, wt. loss is often not quantifiable during the critical illness phase, with severe edema masking non-fluid related body wt. changes. Energy (kcal) deficits can be used to estimate wt. loss until the edema has resolved, but previous studies in non-burn patients indicate that actual wt. loss is less than the commonly used 3500 kcal per pound of fat (7700 kcal per kg of fat). The objective of this performance improvement project was to evaluate nutritional intake and the resulting dry wt. change in severely burned patients. Methods This performance improvement project was approved by our regulatory compliance division. We performed a retrospective evaluation on patients with at least 20% total body surface area (TBSA) burns admitted for initial burn care to our intensive care unit over a 7-year period. Patients who died or who had major fascial excisions or limb amputations were excluded. Patients who did not achieve a recorded dry wt. after wound healing were not included in this analysis. Retrospective data were collected, including sex, age, burn size, kcal intake, kcal goal per the Milner equation using activity factor of 1.4, admission dry wt., dry wt. after wound healing (defined as less than 10% TBSA open wound), and days to dry wt. after wound healing. Descriptive statistics and linear regression were performed using JMP. Significance was set at p&lt; 0.05. Results The 30 included patients had the following characteristics: 90% male, 30 ± 11 years old, 45% ± 15% TBSA burn. They received 2720 ± 1092 kcal/day, meeting 68% ± 24% kcal goal, and took approximately 53 ± 30 days from injury to achieve dry wt. after wound healing. These patients had wt. loss of 8 ± 8 kg from the kcal deficit of 69,819 ± 51,704 during this time period. The kcal deficit was significantly associated with wt. change [p &lt; 0.001, R2 = 0.49, wt. change in kg = (-0.000103 x kcal deficit) – 1]. This translates to one kg of body wt. loss resulting from 9709 kcal deficit. Conclusions This performance improvement project found that an energy deficit of approximately 9700 kcal in our patients equates to 1 kg of body mass loss (4400 kcal deficit equates to 1 pound of body mass loss). These findings are similar to wt. loss studies in other patient populations and contrary to the commonly used 3500 kcal per pound of fat (7700 kcal per kg of fat).


2021 ◽  
Vol 10 (11) ◽  
pp. 2272
Author(s):  
Kai Ushio ◽  
Yukio Mikami ◽  
Hiromune Obayashi ◽  
Hironori Fujishita ◽  
Kouki Fukuhara ◽  
...  

Decreased muscle-to-fat mass ratio (MFR) is associated with pediatric nonalcoholic fatty liver disease (NAFLD) and may reduce muscular fitness. Regular exercise in sports clubs has not led to reductions in obesity in children and adolescents; they may have decreased MFR. Decreased MFR could cause reduced muscular fitness, which may put them at risk for NAFLD development. We investigated whether MFR is related to muscular fitness and serum alanine aminotransferase (ALT), to determine whether MFR could be used to screen for NAFLD in children and adolescent boys belonging to sports clubs. Altogether, 113 participants (aged 7–17 years) who underwent body composition, laboratory, and muscular fitness measurements during a medical checkup were divided into tertiles according to their MFR. Lower extremity muscular fitness values were significantly decreased in the lowest MFR tertile (p < 0.001); conversely, serum ALT levels were significantly increased (p < 0.01). Decreased MFR significantly increased the risk of elevated ALT, which requires screening for NAFLD, after adjusting for age, obesity, muscular fitness parameters, and metabolic risk factors (odds ratio = 8.53, 95% confidence interval = 1.60–45.6, p = 0.012). Physical fitness and body composition assessments, focusing on MFR, can be useful in improving performance and screening for NAFLD in children and adolescents exercising in sports clubs.


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